0,0 → 1,2600 |
=encoding utf8 |
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=head1 NAME |
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ffmpeg-devices - FFmpeg devices |
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=head1 DESCRIPTION |
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This document describes the input and output devices provided by the |
libavdevice library. |
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=head1 DEVICE OPTIONS |
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The libavdevice library provides the same interface as |
libavformat. Namely, an input device is considered like a demuxer, and |
an output device like a muxer, and the interface and generic device |
options are the same provided by libavformat (see the ffmpeg-formats |
manual). |
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In addition each input or output device may support so-called private |
options, which are specific for that component. |
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Options may be set by specifying -I<option> I<value> in the |
FFmpeg tools, or by setting the value explicitly in the device |
C<AVFormatContext> options or using the F<libavutil/opt.h> API |
for programmatic use. |
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=head1 INPUT DEVICES |
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Input devices are configured elements in FFmpeg which enable accessing |
the data coming from a multimedia device attached to your system. |
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When you configure your FFmpeg build, all the supported input devices |
are enabled by default. You can list all available ones using the |
configure option "--list-indevs". |
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You can disable all the input devices using the configure option |
"--disable-indevs", and selectively enable an input device using the |
option "--enable-indev=I<INDEV>", or you can disable a particular |
input device using the option "--disable-indev=I<INDEV>". |
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The option "-devices" of the ff* tools will display the list of |
supported input devices. |
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A description of the currently available input devices follows. |
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=head2 alsa |
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ALSA (Advanced Linux Sound Architecture) input device. |
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To enable this input device during configuration you need libasound |
installed on your system. |
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This device allows capturing from an ALSA device. The name of the |
device to capture has to be an ALSA card identifier. |
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An ALSA identifier has the syntax: |
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hw:<CARD>[,<DEV>[,<SUBDEV>]] |
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where the I<DEV> and I<SUBDEV> components are optional. |
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The three arguments (in order: I<CARD>,I<DEV>,I<SUBDEV>) |
specify card number or identifier, device number and subdevice number |
(-1 means any). |
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To see the list of cards currently recognized by your system check the |
files F</proc/asound/cards> and F</proc/asound/devices>. |
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For example to capture with B<ffmpeg> from an ALSA device with |
card id 0, you may run the command: |
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ffmpeg -f alsa -i hw:0 alsaout.wav |
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For more information see: |
E<lt>B<http://www.alsa-project.org/alsa-doc/alsa-lib/pcm.html>E<gt> |
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=head3 Options |
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=over 4 |
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=item B<sample_rate> |
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Set the sample rate in Hz. Default is 48000. |
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=item B<channels> |
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Set the number of channels. Default is 2. |
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=back |
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=head2 avfoundation |
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AVFoundation input device. |
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AVFoundation is the currently recommended framework by Apple for streamgrabbing on OSX E<gt>= 10.7 as well as on iOS. |
The older QTKit framework has been marked deprecated since OSX version 10.7. |
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The input filename has to be given in the following syntax: |
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-i "[[VIDEO]:[AUDIO]]" |
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The first entry selects the video input while the latter selects the audio input. |
The stream has to be specified by the device name or the device index as shown by the device list. |
Alternatively, the video and/or audio input device can be chosen by index using the |
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B<-video_device_index E<lt>INDEXE<gt>> |
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and/or |
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B<-audio_device_index E<lt>INDEXE<gt>> |
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, overriding any |
device name or index given in the input filename. |
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All available devices can be enumerated by using B<-list_devices true>, listing |
all device names and corresponding indices. |
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There are two device name aliases: |
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=over 4 |
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=item C<default> |
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Select the AVFoundation default device of the corresponding type. |
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=item C<none> |
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Do not record the corresponding media type. |
This is equivalent to specifying an empty device name or index. |
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=back |
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=head3 Options |
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AVFoundation supports the following options: |
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=over 4 |
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=item B<-list_devices E<lt>TRUE|FALSEE<gt>> |
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If set to true, a list of all available input devices is given showing all |
device names and indices. |
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=item B<-video_device_index E<lt>INDEXE<gt>> |
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Specify the video device by its index. Overrides anything given in the input filename. |
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=item B<-audio_device_index E<lt>INDEXE<gt>> |
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Specify the audio device by its index. Overrides anything given in the input filename. |
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=item B<-pixel_format E<lt>FORMATE<gt>> |
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Request the video device to use a specific pixel format. |
If the specified format is not supported, a list of available formats is given |
und the first one in this list is used instead. Available pixel formats are: |
C<monob, rgb555be, rgb555le, rgb565be, rgb565le, rgb24, bgr24, 0rgb, bgr0, 0bgr, rgb0, |
bgr48be, uyvy422, yuva444p, yuva444p16le, yuv444p, yuv422p16, yuv422p10, yuv444p10, |
yuv420p, nv12, yuyv422, gray> |
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=item B<-framerate> |
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Set the grabbing frame rate. Default is C<ntsc>, corresponding to a |
frame rate of C<30000/1001>. |
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=item B<-video_size> |
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Set the video frame size. |
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=item B<-capture_cursor> |
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Capture the mouse pointer. Default is 0. |
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=item B<-capture_mouse_clicks> |
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Capture the screen mouse clicks. Default is 0. |
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=back |
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=head3 Examples |
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=over 4 |
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=item * |
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Print the list of AVFoundation supported devices and exit: |
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$ ffmpeg -f avfoundation -list_devices true -i "" |
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=item * |
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Record video from video device 0 and audio from audio device 0 into out.avi: |
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$ ffmpeg -f avfoundation -i "0:0" out.avi |
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=item * |
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Record video from video device 2 and audio from audio device 1 into out.avi: |
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$ ffmpeg -f avfoundation -video_device_index 2 -i ":1" out.avi |
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=item * |
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Record video from the system default video device using the pixel format bgr0 and do not record any audio into out.avi: |
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$ ffmpeg -f avfoundation -pixel_format bgr0 -i "default:none" out.avi |
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=back |
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=head2 bktr |
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BSD video input device. |
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=head3 Options |
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=over 4 |
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=item B<framerate> |
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Set the frame rate. |
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=item B<video_size> |
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Set the video frame size. Default is C<vga>. |
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=item B<standard> |
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Available values are: |
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=over 4 |
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=item B<pal> |
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=item B<ntsc> |
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=item B<secam> |
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=item B<paln> |
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=item B<palm> |
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=item B<ntscj> |
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=back |
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=back |
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=head2 decklink |
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The decklink input device provides capture capabilities for Blackmagic |
DeckLink devices. |
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To enable this input device, you need the Blackmagic DeckLink SDK and you |
need to configure with the appropriate C<--extra-cflags> |
and C<--extra-ldflags>. |
On Windows, you need to run the IDL files through B<widl>. |
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DeckLink is very picky about the formats it supports. Pixel format is |
uyvy422 or v210, framerate and video size must be determined for your device with |
B<-list_formats 1>. Audio sample rate is always 48 kHz and the number |
of channels can be 2, 8 or 16. |
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=head3 Options |
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=over 4 |
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=item B<list_devices> |
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If set to B<true>, print a list of devices and exit. |
Defaults to B<false>. |
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=item B<list_formats> |
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If set to B<true>, print a list of supported formats and exit. |
Defaults to B<false>. |
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=item B<bm_v210> |
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If set to B<1>, video is captured in 10 bit v210 instead |
of uyvy422. Not all Blackmagic devices support this option. |
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=back |
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=head3 Examples |
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=over 4 |
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=item * |
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List input devices: |
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ffmpeg -f decklink -list_devices 1 -i dummy |
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=item * |
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List supported formats: |
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ffmpeg -f decklink -list_formats 1 -i 'Intensity Pro' |
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=item * |
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Capture video clip at 1080i50 (format 11): |
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ffmpeg -f decklink -i 'Intensity Pro@11' -acodec copy -vcodec copy output.avi |
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=item * |
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Capture video clip at 1080i50 10 bit: |
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ffmpeg -bm_v210 1 -f decklink -i 'UltraStudio Mini Recorder@11' -acodec copy -vcodec copy output.avi |
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=back |
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=head2 dshow |
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Windows DirectShow input device. |
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DirectShow support is enabled when FFmpeg is built with the mingw-w64 project. |
Currently only audio and video devices are supported. |
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Multiple devices may be opened as separate inputs, but they may also be |
opened on the same input, which should improve synchronism between them. |
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The input name should be in the format: |
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<TYPE>=<NAME>[:<TYPE>=<NAME>] |
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where I<TYPE> can be either I<audio> or I<video>, |
and I<NAME> is the device's name or alternative name.. |
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=head3 Options |
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If no options are specified, the device's defaults are used. |
If the device does not support the requested options, it will |
fail to open. |
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=over 4 |
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=item B<video_size> |
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Set the video size in the captured video. |
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=item B<framerate> |
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Set the frame rate in the captured video. |
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=item B<sample_rate> |
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Set the sample rate (in Hz) of the captured audio. |
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=item B<sample_size> |
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Set the sample size (in bits) of the captured audio. |
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=item B<channels> |
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Set the number of channels in the captured audio. |
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=item B<list_devices> |
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If set to B<true>, print a list of devices and exit. |
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=item B<list_options> |
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If set to B<true>, print a list of selected device's options |
and exit. |
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=item B<video_device_number> |
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Set video device number for devices with the same name (starts at 0, |
defaults to 0). |
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=item B<audio_device_number> |
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Set audio device number for devices with the same name (starts at 0, |
defaults to 0). |
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=item B<pixel_format> |
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Select pixel format to be used by DirectShow. This may only be set when |
the video codec is not set or set to rawvideo. |
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=item B<audio_buffer_size> |
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Set audio device buffer size in milliseconds (which can directly |
impact latency, depending on the device). |
Defaults to using the audio device's |
default buffer size (typically some multiple of 500ms). |
Setting this value too low can degrade performance. |
See also |
E<lt>B<http://msdn.microsoft.com/en-us/library/windows/desktop/dd377582(v=vs.85).aspx>E<gt> |
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=item B<video_pin_name> |
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Select video capture pin to use by name or alternative name. |
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=item B<audio_pin_name> |
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Select audio capture pin to use by name or alternative name. |
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=item B<crossbar_video_input_pin_number> |
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Select video input pin number for crossbar device. This will be |
routed to the crossbar device's Video Decoder output pin. |
Note that changing this value can affect future invocations |
(sets a new default) until system reboot occurs. |
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=item B<crossbar_audio_input_pin_number> |
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Select audio input pin number for crossbar device. This will be |
routed to the crossbar device's Audio Decoder output pin. |
Note that changing this value can affect future invocations |
(sets a new default) until system reboot occurs. |
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=item B<show_video_device_dialog> |
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If set to B<true>, before capture starts, popup a display dialog |
to the end user, allowing them to change video filter properties |
and configurations manually. |
Note that for crossbar devices, adjusting values in this dialog |
may be needed at times to toggle between PAL (25 fps) and NTSC (29.97) |
input frame rates, sizes, interlacing, etc. Changing these values can |
enable different scan rates/frame rates and avoiding green bars at |
the bottom, flickering scan lines, etc. |
Note that with some devices, changing these properties can also affect future |
invocations (sets new defaults) until system reboot occurs. |
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=item B<show_audio_device_dialog> |
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If set to B<true>, before capture starts, popup a display dialog |
to the end user, allowing them to change audio filter properties |
and configurations manually. |
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=item B<show_video_crossbar_connection_dialog> |
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If set to B<true>, before capture starts, popup a display |
dialog to the end user, allowing them to manually |
modify crossbar pin routings, when it opens a video device. |
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=item B<show_audio_crossbar_connection_dialog> |
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If set to B<true>, before capture starts, popup a display |
dialog to the end user, allowing them to manually |
modify crossbar pin routings, when it opens an audio device. |
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=item B<show_analog_tv_tuner_dialog> |
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If set to B<true>, before capture starts, popup a display |
dialog to the end user, allowing them to manually |
modify TV channels and frequencies. |
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=item B<show_analog_tv_tuner_audio_dialog> |
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If set to B<true>, before capture starts, popup a display |
dialog to the end user, allowing them to manually |
modify TV audio (like mono vs. stereo, Language A,B or C). |
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=item B<audio_device_load> |
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Load an audio capture filter device from file instead of searching |
it by name. It may load additional parameters too, if the filter |
supports the serialization of its properties to. |
To use this an audio capture source has to be specified, but it can |
be anything even fake one. |
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=item B<audio_device_save> |
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Save the currently used audio capture filter device and its |
parameters (if the filter supports it) to a file. |
If a file with the same name exists it will be overwritten. |
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=item B<video_device_load> |
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Load a video capture filter device from file instead of searching |
it by name. It may load additional parameters too, if the filter |
supports the serialization of its properties to. |
To use this a video capture source has to be specified, but it can |
be anything even fake one. |
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=item B<video_device_save> |
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Save the currently used video capture filter device and its |
parameters (if the filter supports it) to a file. |
If a file with the same name exists it will be overwritten. |
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=back |
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=head3 Examples |
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=over 4 |
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=item * |
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Print the list of DirectShow supported devices and exit: |
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$ ffmpeg -list_devices true -f dshow -i dummy |
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=item * |
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Open video device I<Camera>: |
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$ ffmpeg -f dshow -i video="Camera" |
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=item * |
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Open second video device with name I<Camera>: |
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$ ffmpeg -f dshow -video_device_number 1 -i video="Camera" |
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=item * |
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Open video device I<Camera> and audio device I<Microphone>: |
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$ ffmpeg -f dshow -i video="Camera":audio="Microphone" |
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=item * |
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Print the list of supported options in selected device and exit: |
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$ ffmpeg -list_options true -f dshow -i video="Camera" |
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=item * |
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Specify pin names to capture by name or alternative name, specify alternative device name: |
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$ ffmpeg -f dshow -audio_pin_name "Audio Out" -video_pin_name 2 -i video=video="@device_pnp_\\?\pci#ven_1a0a&dev_6200&subsys_62021461&rev_01#4&e2c7dd6&0&00e1#{65e8773d-8f56-11d0-a3b9-00a0c9223196}\{ca465100-deb0-4d59-818f-8c477184adf6}":audio="Microphone" |
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=item * |
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Configure a crossbar device, specifying crossbar pins, allow user to adjust video capture properties at startup: |
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$ ffmpeg -f dshow -show_video_device_dialog true -crossbar_video_input_pin_number 0 |
-crossbar_audio_input_pin_number 3 -i video="AVerMedia BDA Analog Capture":audio="AVerMedia BDA Analog Capture" |
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=back |
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=head2 dv1394 |
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Linux DV 1394 input device. |
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=head3 Options |
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=over 4 |
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=item B<framerate> |
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Set the frame rate. Default is 25. |
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=item B<standard> |
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Available values are: |
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=over 4 |
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=item B<pal> |
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=item B<ntsc> |
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=back |
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Default value is C<ntsc>. |
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=back |
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=head2 fbdev |
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Linux framebuffer input device. |
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The Linux framebuffer is a graphic hardware-independent abstraction |
layer to show graphics on a computer monitor, typically on the |
console. It is accessed through a file device node, usually |
F</dev/fb0>. |
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For more detailed information read the file |
Documentation/fb/framebuffer.txt included in the Linux source tree. |
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See also E<lt>B<http://linux-fbdev.sourceforge.net/>E<gt>, and fbset(1). |
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To record from the framebuffer device F</dev/fb0> with |
B<ffmpeg>: |
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ffmpeg -f fbdev -framerate 10 -i /dev/fb0 out.avi |
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You can take a single screenshot image with the command: |
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ffmpeg -f fbdev -framerate 1 -i /dev/fb0 -frames:v 1 screenshot.jpeg |
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=head3 Options |
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=over 4 |
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=item B<framerate> |
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Set the frame rate. Default is 25. |
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=back |
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=head2 gdigrab |
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Win32 GDI-based screen capture device. |
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This device allows you to capture a region of the display on Windows. |
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There are two options for the input filename: |
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desktop |
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or |
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title=<window_title> |
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The first option will capture the entire desktop, or a fixed region of the |
desktop. The second option will instead capture the contents of a single |
window, regardless of its position on the screen. |
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For example, to grab the entire desktop using B<ffmpeg>: |
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ffmpeg -f gdigrab -framerate 6 -i desktop out.mpg |
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Grab a 640x480 region at position C<10,20>: |
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ffmpeg -f gdigrab -framerate 6 -offset_x 10 -offset_y 20 -video_size vga -i desktop out.mpg |
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Grab the contents of the window named "Calculator" |
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ffmpeg -f gdigrab -framerate 6 -i title=Calculator out.mpg |
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=head3 Options |
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=over 4 |
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=item B<draw_mouse> |
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Specify whether to draw the mouse pointer. Use the value C<0> to |
not draw the pointer. Default value is C<1>. |
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=item B<framerate> |
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Set the grabbing frame rate. Default value is C<ntsc>, |
corresponding to a frame rate of C<30000/1001>. |
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=item B<show_region> |
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Show grabbed region on screen. |
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If I<show_region> is specified with C<1>, then the grabbing |
region will be indicated on screen. With this option, it is easy to |
know what is being grabbed if only a portion of the screen is grabbed. |
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Note that I<show_region> is incompatible with grabbing the contents |
of a single window. |
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For example: |
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ffmpeg -f gdigrab -show_region 1 -framerate 6 -video_size cif -offset_x 10 -offset_y 20 -i desktop out.mpg |
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=item B<video_size> |
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Set the video frame size. The default is to capture the full screen if F<desktop> is selected, or the full window size if F<title=I<window_title>> is selected. |
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=item B<offset_x> |
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When capturing a region with I<video_size>, set the distance from the left edge of the screen or desktop. |
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Note that the offset calculation is from the top left corner of the primary monitor on Windows. If you have a monitor positioned to the left of your primary monitor, you will need to use a negative I<offset_x> value to move the region to that monitor. |
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=item B<offset_y> |
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When capturing a region with I<video_size>, set the distance from the top edge of the screen or desktop. |
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Note that the offset calculation is from the top left corner of the primary monitor on Windows. If you have a monitor positioned above your primary monitor, you will need to use a negative I<offset_y> value to move the region to that monitor. |
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=back |
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=head2 iec61883 |
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FireWire DV/HDV input device using libiec61883. |
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To enable this input device, you need libiec61883, libraw1394 and |
libavc1394 installed on your system. Use the configure option |
C<--enable-libiec61883> to compile with the device enabled. |
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The iec61883 capture device supports capturing from a video device |
connected via IEEE1394 (FireWire), using libiec61883 and the new Linux |
FireWire stack (juju). This is the default DV/HDV input method in Linux |
Kernel 2.6.37 and later, since the old FireWire stack was removed. |
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Specify the FireWire port to be used as input file, or "auto" |
to choose the first port connected. |
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=head3 Options |
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=over 4 |
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=item B<dvtype> |
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Override autodetection of DV/HDV. This should only be used if auto |
detection does not work, or if usage of a different device type |
should be prohibited. Treating a DV device as HDV (or vice versa) will |
not work and result in undefined behavior. |
The values B<auto>, B<dv> and B<hdv> are supported. |
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=item B<dvbuffer> |
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Set maximum size of buffer for incoming data, in frames. For DV, this |
is an exact value. For HDV, it is not frame exact, since HDV does |
not have a fixed frame size. |
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=item B<dvguid> |
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Select the capture device by specifying it's GUID. Capturing will only |
be performed from the specified device and fails if no device with the |
given GUID is found. This is useful to select the input if multiple |
devices are connected at the same time. |
Look at /sys/bus/firewire/devices to find out the GUIDs. |
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=back |
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=head3 Examples |
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=over 4 |
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=item * |
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Grab and show the input of a FireWire DV/HDV device. |
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ffplay -f iec61883 -i auto |
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=item * |
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Grab and record the input of a FireWire DV/HDV device, |
using a packet buffer of 100000 packets if the source is HDV. |
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ffmpeg -f iec61883 -i auto -hdvbuffer 100000 out.mpg |
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=back |
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=head2 jack |
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JACK input device. |
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To enable this input device during configuration you need libjack |
installed on your system. |
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A JACK input device creates one or more JACK writable clients, one for |
each audio channel, with name I<client_name>:input_I<N>, where |
I<client_name> is the name provided by the application, and I<N> |
is a number which identifies the channel. |
Each writable client will send the acquired data to the FFmpeg input |
device. |
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Once you have created one or more JACK readable clients, you need to |
connect them to one or more JACK writable clients. |
|
To connect or disconnect JACK clients you can use the B<jack_connect> |
and B<jack_disconnect> programs, or do it through a graphical interface, |
for example with B<qjackctl>. |
|
To list the JACK clients and their properties you can invoke the command |
B<jack_lsp>. |
|
Follows an example which shows how to capture a JACK readable client |
with B<ffmpeg>. |
|
# Create a JACK writable client with name "ffmpeg". |
$ ffmpeg -f jack -i ffmpeg -y out.wav |
|
# Start the sample jack_metro readable client. |
$ jack_metro -b 120 -d 0.2 -f 4000 |
|
# List the current JACK clients. |
$ jack_lsp -c |
system:capture_1 |
system:capture_2 |
system:playback_1 |
system:playback_2 |
ffmpeg:input_1 |
metro:120_bpm |
|
# Connect metro to the ffmpeg writable client. |
$ jack_connect metro:120_bpm ffmpeg:input_1 |
|
|
For more information read: |
E<lt>B<http://jackaudio.org/>E<gt> |
|
|
=head3 Options |
|
|
|
=over 4 |
|
|
|
=item B<channels> |
|
Set the number of channels. Default is 2. |
|
|
=back |
|
|
|
=head2 lavfi |
|
|
Libavfilter input virtual device. |
|
This input device reads data from the open output pads of a libavfilter |
filtergraph. |
|
For each filtergraph open output, the input device will create a |
corresponding stream which is mapped to the generated output. Currently |
only video data is supported. The filtergraph is specified through the |
option B<graph>. |
|
|
=head3 Options |
|
|
|
=over 4 |
|
|
|
=item B<graph> |
|
Specify the filtergraph to use as input. Each video open output must be |
labelled by a unique string of the form "outI<N>", where I<N> is a |
number starting from 0 corresponding to the mapped input stream |
generated by the device. |
The first unlabelled output is automatically assigned to the "out0" |
label, but all the others need to be specified explicitly. |
|
The suffix "+subcc" can be appended to the output label to create an extra |
stream with the closed captions packets attached to that output |
(experimental; only for EIA-608 / CEA-708 for now). |
The subcc streams are created after all the normal streams, in the order of |
the corresponding stream. |
For example, if there is "out19+subcc", "out7+subcc" and up to "out42", the |
stream #43 is subcc for stream #7 and stream #44 is subcc for stream #19. |
|
If not specified defaults to the filename specified for the input |
device. |
|
|
=item B<graph_file> |
|
Set the filename of the filtergraph to be read and sent to the other |
filters. Syntax of the filtergraph is the same as the one specified by |
the option I<graph>. |
|
|
=item B<dumpgraph> |
|
Dump graph to stderr. |
|
|
=back |
|
|
|
=head3 Examples |
|
|
|
=over 4 |
|
|
=item * |
|
Create a color video stream and play it back with B<ffplay>: |
|
ffplay -f lavfi -graph "color=c=pink [out0]" dummy |
|
|
|
=item * |
|
As the previous example, but use filename for specifying the graph |
description, and omit the "out0" label: |
|
ffplay -f lavfi color=c=pink |
|
|
|
=item * |
|
Create three different video test filtered sources and play them: |
|
ffplay -f lavfi -graph "testsrc [out0]; testsrc,hflip [out1]; testsrc,negate [out2]" test3 |
|
|
|
=item * |
|
Read an audio stream from a file using the amovie source and play it |
back with B<ffplay>: |
|
ffplay -f lavfi "amovie=test.wav" |
|
|
|
=item * |
|
Read an audio stream and a video stream and play it back with |
B<ffplay>: |
|
ffplay -f lavfi "movie=test.avi[out0];amovie=test.wav[out1]" |
|
|
|
=item * |
|
Dump decoded frames to images and closed captions to a file (experimental): |
|
ffmpeg -f lavfi -i "movie=test.ts[out0+subcc]" -map v frame%08d.png -map s -c copy -f rawvideo subcc.bin |
|
|
|
=back |
|
|
|
=head2 libcdio |
|
|
Audio-CD input device based on libcdio. |
|
To enable this input device during configuration you need libcdio |
installed on your system. It requires the configure option |
C<--enable-libcdio>. |
|
This device allows playing and grabbing from an Audio-CD. |
|
For example to copy with B<ffmpeg> the entire Audio-CD in F</dev/sr0>, |
you may run the command: |
|
ffmpeg -f libcdio -i /dev/sr0 cd.wav |
|
|
|
=head3 Options |
|
|
=over 4 |
|
|
=item B<speed> |
|
Set drive reading speed. Default value is 0. |
|
The speed is specified CD-ROM speed units. The speed is set through |
the libcdio C<cdio_cddap_speed_set> function. On many CD-ROM |
drives, specifying a value too large will result in using the fastest |
speed. |
|
|
=item B<paranoia_mode> |
|
Set paranoia recovery mode flags. It accepts one of the following values: |
|
|
=over 4 |
|
|
=item B<disable> |
|
|
=item B<verify> |
|
|
=item B<overlap> |
|
|
=item B<neverskip> |
|
|
=item B<full> |
|
|
=back |
|
|
Default value is B<disable>. |
|
For more information about the available recovery modes, consult the |
paranoia project documentation. |
|
=back |
|
|
|
=head2 libdc1394 |
|
|
IIDC1394 input device, based on libdc1394 and libraw1394. |
|
Requires the configure option C<--enable-libdc1394>. |
|
|
=head2 openal |
|
|
The OpenAL input device provides audio capture on all systems with a |
working OpenAL 1.1 implementation. |
|
To enable this input device during configuration, you need OpenAL |
headers and libraries installed on your system, and need to configure |
FFmpeg with C<--enable-openal>. |
|
OpenAL headers and libraries should be provided as part of your OpenAL |
implementation, or as an additional download (an SDK). Depending on your |
installation you may need to specify additional flags via the |
C<--extra-cflags> and C<--extra-ldflags> for allowing the build |
system to locate the OpenAL headers and libraries. |
|
An incomplete list of OpenAL implementations follows: |
|
|
=over 4 |
|
|
=item B<Creative> |
|
The official Windows implementation, providing hardware acceleration |
with supported devices and software fallback. |
See E<lt>B<http://openal.org/>E<gt>. |
|
=item B<OpenAL Soft> |
|
Portable, open source (LGPL) software implementation. Includes |
backends for the most common sound APIs on the Windows, Linux, |
Solaris, and BSD operating systems. |
See E<lt>B<http://kcat.strangesoft.net/openal.html>E<gt>. |
|
=item B<Apple> |
|
OpenAL is part of Core Audio, the official Mac OS X Audio interface. |
See E<lt>B<http://developer.apple.com/technologies/mac/audio-and-video.html>E<gt> |
|
=back |
|
|
This device allows one to capture from an audio input device handled |
through OpenAL. |
|
You need to specify the name of the device to capture in the provided |
filename. If the empty string is provided, the device will |
automatically select the default device. You can get the list of the |
supported devices by using the option I<list_devices>. |
|
|
=head3 Options |
|
|
|
=over 4 |
|
|
|
=item B<channels> |
|
Set the number of channels in the captured audio. Only the values |
B<1> (monaural) and B<2> (stereo) are currently supported. |
Defaults to B<2>. |
|
|
=item B<sample_size> |
|
Set the sample size (in bits) of the captured audio. Only the values |
B<8> and B<16> are currently supported. Defaults to |
B<16>. |
|
|
=item B<sample_rate> |
|
Set the sample rate (in Hz) of the captured audio. |
Defaults to B<44.1k>. |
|
|
=item B<list_devices> |
|
If set to B<true>, print a list of devices and exit. |
Defaults to B<false>. |
|
|
=back |
|
|
|
=head3 Examples |
|
|
Print the list of OpenAL supported devices and exit: |
|
$ ffmpeg -list_devices true -f openal -i dummy out.ogg |
|
|
Capture from the OpenAL device F<DR-BT101 via PulseAudio>: |
|
$ ffmpeg -f openal -i 'DR-BT101 via PulseAudio' out.ogg |
|
|
Capture from the default device (note the empty string '' as filename): |
|
$ ffmpeg -f openal -i '' out.ogg |
|
|
Capture from two devices simultaneously, writing to two different files, |
within the same B<ffmpeg> command: |
|
$ ffmpeg -f openal -i 'DR-BT101 via PulseAudio' out1.ogg -f openal -i 'ALSA Default' out2.ogg |
|
Note: not all OpenAL implementations support multiple simultaneous capture - |
try the latest OpenAL Soft if the above does not work. |
|
|
=head2 oss |
|
|
Open Sound System input device. |
|
The filename to provide to the input device is the device node |
representing the OSS input device, and is usually set to |
F</dev/dsp>. |
|
For example to grab from F</dev/dsp> using B<ffmpeg> use the |
command: |
|
ffmpeg -f oss -i /dev/dsp /tmp/oss.wav |
|
|
For more information about OSS see: |
E<lt>B<http://manuals.opensound.com/usersguide/dsp.html>E<gt> |
|
|
=head3 Options |
|
|
|
=over 4 |
|
|
|
=item B<sample_rate> |
|
Set the sample rate in Hz. Default is 48000. |
|
|
=item B<channels> |
|
Set the number of channels. Default is 2. |
|
|
=back |
|
|
|
|
=head2 pulse |
|
|
PulseAudio input device. |
|
To enable this output device you need to configure FFmpeg with C<--enable-libpulse>. |
|
The filename to provide to the input device is a source device or the |
string "default" |
|
To list the PulseAudio source devices and their properties you can invoke |
the command B<pactl list sources>. |
|
More information about PulseAudio can be found on E<lt>B<http://www.pulseaudio.org>E<gt>. |
|
|
=head3 Options |
|
|
=over 4 |
|
|
=item B<server> |
|
Connect to a specific PulseAudio server, specified by an IP address. |
Default server is used when not provided. |
|
|
=item B<name> |
|
Specify the application name PulseAudio will use when showing active clients, |
by default it is the C<LIBAVFORMAT_IDENT> string. |
|
|
=item B<stream_name> |
|
Specify the stream name PulseAudio will use when showing active streams, |
by default it is "record". |
|
|
=item B<sample_rate> |
|
Specify the samplerate in Hz, by default 48kHz is used. |
|
|
=item B<channels> |
|
Specify the channels in use, by default 2 (stereo) is set. |
|
|
=item B<frame_size> |
|
Specify the number of bytes per frame, by default it is set to 1024. |
|
|
=item B<fragment_size> |
|
Specify the minimal buffering fragment in PulseAudio, it will affect the |
audio latency. By default it is unset. |
|
|
=item B<wallclock> |
|
Set the initial PTS using the current time. Default is 1. |
|
|
=back |
|
|
|
=head3 Examples |
|
Record a stream from default device: |
|
ffmpeg -f pulse -i default /tmp/pulse.wav |
|
|
|
=head2 qtkit |
|
|
QTKit input device. |
|
The filename passed as input is parsed to contain either a device name or index. |
The device index can also be given by using -video_device_index. |
A given device index will override any given device name. |
If the desired device consists of numbers only, use -video_device_index to identify it. |
The default device will be chosen if an empty string or the device name "default" is given. |
The available devices can be enumerated by using -list_devices. |
|
|
ffmpeg -f qtkit -i "0" out.mpg |
|
|
|
ffmpeg -f qtkit -video_device_index 0 -i "" out.mpg |
|
|
|
ffmpeg -f qtkit -i "default" out.mpg |
|
|
|
ffmpeg -f qtkit -list_devices true -i "" |
|
|
|
=head3 Options |
|
|
|
=over 4 |
|
|
|
=item B<frame_rate> |
|
Set frame rate. Default is 30. |
|
|
=item B<list_devices> |
|
If set to C<true>, print a list of devices and exit. Default is |
C<false>. |
|
|
=item B<video_device_index> |
|
Select the video device by index for devices with the same name (starts at 0). |
|
|
=back |
|
|
|
=head2 sndio |
|
|
sndio input device. |
|
To enable this input device during configuration you need libsndio |
installed on your system. |
|
The filename to provide to the input device is the device node |
representing the sndio input device, and is usually set to |
F</dev/audio0>. |
|
For example to grab from F</dev/audio0> using B<ffmpeg> use the |
command: |
|
ffmpeg -f sndio -i /dev/audio0 /tmp/oss.wav |
|
|
|
=head3 Options |
|
|
|
=over 4 |
|
|
|
=item B<sample_rate> |
|
Set the sample rate in Hz. Default is 48000. |
|
|
=item B<channels> |
|
Set the number of channels. Default is 2. |
|
|
=back |
|
|
|
=head2 video4linux2, v4l2 |
|
|
Video4Linux2 input video device. |
|
"v4l2" can be used as alias for "video4linux2". |
|
If FFmpeg is built with v4l-utils support (by using the |
C<--enable-libv4l2> configure option), it is possible to use it with the |
C<-use_libv4l2> input device option. |
|
The name of the device to grab is a file device node, usually Linux |
systems tend to automatically create such nodes when the device |
(e.g. an USB webcam) is plugged into the system, and has a name of the |
kind F</dev/videoI<N>>, where I<N> is a number associated to |
the device. |
|
Video4Linux2 devices usually support a limited set of |
I<width>xI<height> sizes and frame rates. You can check which are |
supported using B<-list_formats all> for Video4Linux2 devices. |
Some devices, like TV cards, support one or more standards. It is possible |
to list all the supported standards using B<-list_standards all>. |
|
The time base for the timestamps is 1 microsecond. Depending on the kernel |
version and configuration, the timestamps may be derived from the real time |
clock (origin at the Unix Epoch) or the monotonic clock (origin usually at |
boot time, unaffected by NTP or manual changes to the clock). The |
B<-timestamps abs> or B<-ts abs> option can be used to force |
conversion into the real time clock. |
|
Some usage examples of the video4linux2 device with B<ffmpeg> |
and B<ffplay>: |
|
=over 4 |
|
|
=item * |
|
List supported formats for a video4linux2 device: |
|
ffplay -f video4linux2 -list_formats all /dev/video0 |
|
|
|
=item * |
|
Grab and show the input of a video4linux2 device: |
|
ffplay -f video4linux2 -framerate 30 -video_size hd720 /dev/video0 |
|
|
|
=item * |
|
Grab and record the input of a video4linux2 device, leave the |
frame rate and size as previously set: |
|
ffmpeg -f video4linux2 -input_format mjpeg -i /dev/video0 out.mpeg |
|
|
=back |
|
|
For more information about Video4Linux, check E<lt>B<http://linuxtv.org/>E<gt>. |
|
|
=head3 Options |
|
|
|
=over 4 |
|
|
=item B<standard> |
|
Set the standard. Must be the name of a supported standard. To get a |
list of the supported standards, use the B<list_standards> |
option. |
|
|
=item B<channel> |
|
Set the input channel number. Default to -1, which means using the |
previously selected channel. |
|
|
=item B<video_size> |
|
Set the video frame size. The argument must be a string in the form |
I<WIDTH>xI<HEIGHT> or a valid size abbreviation. |
|
|
=item B<pixel_format> |
|
Select the pixel format (only valid for raw video input). |
|
|
=item B<input_format> |
|
Set the preferred pixel format (for raw video) or a codec name. |
This option allows one to select the input format, when several are |
available. |
|
|
=item B<framerate> |
|
Set the preferred video frame rate. |
|
|
=item B<list_formats> |
|
List available formats (supported pixel formats, codecs, and frame |
sizes) and exit. |
|
Available values are: |
|
=over 4 |
|
|
=item B<all> |
|
Show all available (compressed and non-compressed) formats. |
|
|
=item B<raw> |
|
Show only raw video (non-compressed) formats. |
|
|
=item B<compressed> |
|
Show only compressed formats. |
|
=back |
|
|
|
=item B<list_standards> |
|
List supported standards and exit. |
|
Available values are: |
|
=over 4 |
|
|
=item B<all> |
|
Show all supported standards. |
|
=back |
|
|
|
=item B<timestamps, ts> |
|
Set type of timestamps for grabbed frames. |
|
Available values are: |
|
=over 4 |
|
|
=item B<default> |
|
Use timestamps from the kernel. |
|
|
=item B<abs> |
|
Use absolute timestamps (wall clock). |
|
|
=item B<mono2abs> |
|
Force conversion from monotonic to absolute timestamps. |
|
=back |
|
|
Default value is C<default>. |
|
|
=item B<use_libv4l2> |
|
Use libv4l2 (v4l-utils) conversion functions. Default is 0. |
|
|
=back |
|
|
|
=head2 vfwcap |
|
|
VfW (Video for Windows) capture input device. |
|
The filename passed as input is the capture driver number, ranging from |
0 to 9. You may use "list" as filename to print a list of drivers. Any |
other filename will be interpreted as device number 0. |
|
|
=head3 Options |
|
|
|
=over 4 |
|
|
|
=item B<video_size> |
|
Set the video frame size. |
|
|
=item B<framerate> |
|
Set the grabbing frame rate. Default value is C<ntsc>, |
corresponding to a frame rate of C<30000/1001>. |
|
|
=back |
|
|
|
=head2 x11grab |
|
|
X11 video input device. |
|
To enable this input device during configuration you need libxcb |
installed on your system. It will be automatically detected during |
configuration. |
|
Alternatively, the configure option B<--enable-x11grab> exists |
for legacy Xlib users. |
|
This device allows one to capture a region of an X11 display. |
|
The filename passed as input has the syntax: |
|
[<hostname>]:<display_number>.<screen_number>[+<x_offset>,<y_offset>] |
|
|
I<hostname>:I<display_number>.I<screen_number> specifies the |
X11 display name of the screen to grab from. I<hostname> can be |
omitted, and defaults to "localhost". The environment variable |
B<DISPLAY> contains the default display name. |
|
I<x_offset> and I<y_offset> specify the offsets of the grabbed |
area with respect to the top-left border of the X11 screen. They |
default to 0. |
|
Check the X11 documentation (e.g. B<man X>) for more detailed |
information. |
|
Use the B<xdpyinfo> program for getting basic information about |
the properties of your X11 display (e.g. grep for "name" or |
"dimensions"). |
|
For example to grab from F<:0.0> using B<ffmpeg>: |
|
ffmpeg -f x11grab -framerate 25 -video_size cif -i :0.0 out.mpg |
|
|
Grab at position C<10,20>: |
|
ffmpeg -f x11grab -framerate 25 -video_size cif -i :0.0+10,20 out.mpg |
|
|
|
=head3 Options |
|
|
|
=over 4 |
|
|
=item B<draw_mouse> |
|
Specify whether to draw the mouse pointer. A value of C<0> specify |
not to draw the pointer. Default value is C<1>. |
|
|
=item B<follow_mouse> |
|
Make the grabbed area follow the mouse. The argument can be |
C<centered> or a number of pixels I<PIXELS>. |
|
When it is specified with "centered", the grabbing region follows the mouse |
pointer and keeps the pointer at the center of region; otherwise, the region |
follows only when the mouse pointer reaches within I<PIXELS> (greater than |
zero) to the edge of region. |
|
For example: |
|
ffmpeg -f x11grab -follow_mouse centered -framerate 25 -video_size cif -i :0.0 out.mpg |
|
|
To follow only when the mouse pointer reaches within 100 pixels to edge: |
|
ffmpeg -f x11grab -follow_mouse 100 -framerate 25 -video_size cif -i :0.0 out.mpg |
|
|
|
=item B<framerate> |
|
Set the grabbing frame rate. Default value is C<ntsc>, |
corresponding to a frame rate of C<30000/1001>. |
|
|
=item B<show_region> |
|
Show grabbed region on screen. |
|
If I<show_region> is specified with C<1>, then the grabbing |
region will be indicated on screen. With this option, it is easy to |
know what is being grabbed if only a portion of the screen is grabbed. |
|
|
=item B<region_border> |
|
Set the region border thickness if B<-show_region 1> is used. |
Range is 1 to 128 and default is 3 (XCB-based x11grab only). |
|
For example: |
|
ffmpeg -f x11grab -show_region 1 -framerate 25 -video_size cif -i :0.0+10,20 out.mpg |
|
|
With I<follow_mouse>: |
|
ffmpeg -f x11grab -follow_mouse centered -show_region 1 -framerate 25 -video_size cif -i :0.0 out.mpg |
|
|
|
=item B<video_size> |
|
Set the video frame size. Default value is C<vga>. |
|
|
=item B<use_shm> |
|
Use the MIT-SHM extension for shared memory. Default value is C<1>. |
It may be necessary to disable it for remote displays (legacy x11grab |
only). |
|
=back |
|
|
|
=head3 I<grab_x> I<grab_y> AVOption |
|
|
The syntax is: |
|
-grab_x <x_offset> -grab_y <y_offset> |
|
|
Set the grabbing region coordinates. They are expressed as offset from the top left |
corner of the X11 window. The default value is 0. |
|
|
|
=head1 OUTPUT DEVICES |
|
|
Output devices are configured elements in FFmpeg that can write |
multimedia data to an output device attached to your system. |
|
When you configure your FFmpeg build, all the supported output devices |
are enabled by default. You can list all available ones using the |
configure option "--list-outdevs". |
|
You can disable all the output devices using the configure option |
"--disable-outdevs", and selectively enable an output device using the |
option "--enable-outdev=I<OUTDEV>", or you can disable a particular |
input device using the option "--disable-outdev=I<OUTDEV>". |
|
The option "-devices" of the ff* tools will display the list of |
enabled output devices. |
|
A description of the currently available output devices follows. |
|
|
=head2 alsa |
|
|
ALSA (Advanced Linux Sound Architecture) output device. |
|
|
=head3 Examples |
|
|
|
=over 4 |
|
|
=item * |
|
Play a file on default ALSA device: |
|
ffmpeg -i INPUT -f alsa default |
|
|
|
=item * |
|
Play a file on soundcard 1, audio device 7: |
|
ffmpeg -i INPUT -f alsa hw:1,7 |
|
|
=back |
|
|
|
=head2 caca |
|
|
CACA output device. |
|
This output device allows one to show a video stream in CACA window. |
Only one CACA window is allowed per application, so you can |
have only one instance of this output device in an application. |
|
To enable this output device you need to configure FFmpeg with |
C<--enable-libcaca>. |
libcaca is a graphics library that outputs text instead of pixels. |
|
For more information about libcaca, check: |
E<lt>B<http://caca.zoy.org/wiki/libcaca>E<gt> |
|
|
=head3 Options |
|
|
|
=over 4 |
|
|
|
=item B<window_title> |
|
Set the CACA window title, if not specified default to the filename |
specified for the output device. |
|
|
=item B<window_size> |
|
Set the CACA window size, can be a string of the form |
I<width>xI<height> or a video size abbreviation. |
If not specified it defaults to the size of the input video. |
|
|
=item B<driver> |
|
Set display driver. |
|
|
=item B<algorithm> |
|
Set dithering algorithm. Dithering is necessary |
because the picture being rendered has usually far more colours than |
the available palette. |
The accepted values are listed with C<-list_dither algorithms>. |
|
|
=item B<antialias> |
|
Set antialias method. Antialiasing smoothens the rendered |
image and avoids the commonly seen staircase effect. |
The accepted values are listed with C<-list_dither antialiases>. |
|
|
=item B<charset> |
|
Set which characters are going to be used when rendering text. |
The accepted values are listed with C<-list_dither charsets>. |
|
|
=item B<color> |
|
Set color to be used when rendering text. |
The accepted values are listed with C<-list_dither colors>. |
|
|
=item B<list_drivers> |
|
If set to B<true>, print a list of available drivers and exit. |
|
|
=item B<list_dither> |
|
List available dither options related to the argument. |
The argument must be one of C<algorithms>, C<antialiases>, |
C<charsets>, C<colors>. |
|
=back |
|
|
|
=head3 Examples |
|
|
|
=over 4 |
|
|
=item * |
|
The following command shows the B<ffmpeg> output is an |
CACA window, forcing its size to 80x25: |
|
ffmpeg -i INPUT -vcodec rawvideo -pix_fmt rgb24 -window_size 80x25 -f caca - |
|
|
|
=item * |
|
Show the list of available drivers and exit: |
|
ffmpeg -i INPUT -pix_fmt rgb24 -f caca -list_drivers true - |
|
|
|
=item * |
|
Show the list of available dither colors and exit: |
|
ffmpeg -i INPUT -pix_fmt rgb24 -f caca -list_dither colors - |
|
|
=back |
|
|
|
=head2 decklink |
|
|
The decklink output device provides playback capabilities for Blackmagic |
DeckLink devices. |
|
To enable this output device, you need the Blackmagic DeckLink SDK and you |
need to configure with the appropriate C<--extra-cflags> |
and C<--extra-ldflags>. |
On Windows, you need to run the IDL files through B<widl>. |
|
DeckLink is very picky about the formats it supports. Pixel format is always |
uyvy422, framerate and video size must be determined for your device with |
B<-list_formats 1>. Audio sample rate is always 48 kHz. |
|
|
=head3 Options |
|
|
|
=over 4 |
|
|
|
=item B<list_devices> |
|
If set to B<true>, print a list of devices and exit. |
Defaults to B<false>. |
|
|
=item B<list_formats> |
|
If set to B<true>, print a list of supported formats and exit. |
Defaults to B<false>. |
|
|
=item B<preroll> |
|
Amount of time to preroll video in seconds. |
Defaults to B<0.5>. |
|
|
=back |
|
|
|
=head3 Examples |
|
|
|
=over 4 |
|
|
|
=item * |
|
List output devices: |
|
ffmpeg -i test.avi -f decklink -list_devices 1 dummy |
|
|
|
=item * |
|
List supported formats: |
|
ffmpeg -i test.avi -f decklink -list_formats 1 'DeckLink Mini Monitor' |
|
|
|
=item * |
|
Play video clip: |
|
ffmpeg -i test.avi -f decklink -pix_fmt uyvy422 'DeckLink Mini Monitor' |
|
|
|
=item * |
|
Play video clip with non-standard framerate or video size: |
|
ffmpeg -i test.avi -f decklink -pix_fmt uyvy422 -s 720x486 -r 24000/1001 'DeckLink Mini Monitor' |
|
|
|
=back |
|
|
|
=head2 fbdev |
|
|
Linux framebuffer output device. |
|
The Linux framebuffer is a graphic hardware-independent abstraction |
layer to show graphics on a computer monitor, typically on the |
console. It is accessed through a file device node, usually |
F</dev/fb0>. |
|
For more detailed information read the file |
F<Documentation/fb/framebuffer.txt> included in the Linux source tree. |
|
|
=head3 Options |
|
|
=over 4 |
|
|
|
=item B<xoffset> |
|
|
=item B<yoffset> |
|
Set x/y coordinate of top left corner. Default is 0. |
|
=back |
|
|
|
=head3 Examples |
|
Play a file on framebuffer device F</dev/fb0>. |
Required pixel format depends on current framebuffer settings. |
|
ffmpeg -re -i INPUT -vcodec rawvideo -pix_fmt bgra -f fbdev /dev/fb0 |
|
|
See also E<lt>B<http://linux-fbdev.sourceforge.net/>E<gt>, and fbset(1). |
|
|
=head2 opengl |
|
OpenGL output device. |
|
To enable this output device you need to configure FFmpeg with C<--enable-opengl>. |
|
This output device allows one to render to OpenGL context. |
Context may be provided by application or default SDL window is created. |
|
When device renders to external context, application must implement handlers for following messages: |
C<AV_DEV_TO_APP_CREATE_WINDOW_BUFFER> - create OpenGL context on current thread. |
C<AV_DEV_TO_APP_PREPARE_WINDOW_BUFFER> - make OpenGL context current. |
C<AV_DEV_TO_APP_DISPLAY_WINDOW_BUFFER> - swap buffers. |
C<AV_DEV_TO_APP_DESTROY_WINDOW_BUFFER> - destroy OpenGL context. |
Application is also required to inform a device about current resolution by sending C<AV_APP_TO_DEV_WINDOW_SIZE> message. |
|
|
=head3 Options |
|
|
=over 4 |
|
|
|
=item B<background> |
|
Set background color. Black is a default. |
|
=item B<no_window> |
|
Disables default SDL window when set to non-zero value. |
Application must provide OpenGL context and both C<window_size_cb> and C<window_swap_buffers_cb> callbacks when set. |
|
=item B<window_title> |
|
Set the SDL window title, if not specified default to the filename specified for the output device. |
Ignored when B<no_window> is set. |
|
=item B<window_size> |
|
Set preferred window size, can be a string of the form widthxheight or a video size abbreviation. |
If not specified it defaults to the size of the input video, downscaled according to the aspect ratio. |
Mostly usable when B<no_window> is not set. |
|
|
=back |
|
|
|
=head3 Examples |
|
Play a file on SDL window using OpenGL rendering: |
|
ffmpeg -i INPUT -f opengl "window title" |
|
|
|
=head2 oss |
|
|
OSS (Open Sound System) output device. |
|
|
=head2 pulse |
|
|
PulseAudio output device. |
|
To enable this output device you need to configure FFmpeg with C<--enable-libpulse>. |
|
More information about PulseAudio can be found on E<lt>B<http://www.pulseaudio.org>E<gt> |
|
|
=head3 Options |
|
|
=over 4 |
|
|
|
=item B<server> |
|
Connect to a specific PulseAudio server, specified by an IP address. |
Default server is used when not provided. |
|
|
=item B<name> |
|
Specify the application name PulseAudio will use when showing active clients, |
by default it is the C<LIBAVFORMAT_IDENT> string. |
|
|
=item B<stream_name> |
|
Specify the stream name PulseAudio will use when showing active streams, |
by default it is set to the specified output name. |
|
|
=item B<device> |
|
Specify the device to use. Default device is used when not provided. |
List of output devices can be obtained with command B<pactl list sinks>. |
|
|
=item B<buffer_size> |
|
|
=item B<buffer_duration> |
|
Control the size and duration of the PulseAudio buffer. A small buffer |
gives more control, but requires more frequent updates. |
|
B<buffer_size> specifies size in bytes while |
B<buffer_duration> specifies duration in milliseconds. |
|
When both options are provided then the highest value is used |
(duration is recalculated to bytes using stream parameters). If they |
are set to 0 (which is default), the device will use the default |
PulseAudio duration value. By default PulseAudio set buffer duration |
to around 2 seconds. |
|
|
=item B<prebuf> |
|
Specify pre-buffering size in bytes. The server does not start with |
playback before at least B<prebuf> bytes are available in the |
buffer. By default this option is initialized to the same value as |
B<buffer_size> or B<buffer_duration> (whichever is bigger). |
|
|
=item B<minreq> |
|
Specify minimum request size in bytes. The server does not request less |
than B<minreq> bytes from the client, instead waits until the buffer |
is free enough to request more bytes at once. It is recommended to not set |
this option, which will initialize this to a value that is deemed sensible |
by the server. |
|
|
=back |
|
|
|
=head3 Examples |
|
Play a file on default device on default server: |
|
ffmpeg -i INPUT -f pulse "stream name" |
|
|
|
=head2 sdl |
|
|
SDL (Simple DirectMedia Layer) output device. |
|
This output device allows one to show a video stream in an SDL |
window. Only one SDL window is allowed per application, so you can |
have only one instance of this output device in an application. |
|
To enable this output device you need libsdl installed on your system |
when configuring your build. |
|
For more information about SDL, check: |
E<lt>B<http://www.libsdl.org/>E<gt> |
|
|
=head3 Options |
|
|
|
=over 4 |
|
|
|
=item B<window_title> |
|
Set the SDL window title, if not specified default to the filename |
specified for the output device. |
|
|
=item B<icon_title> |
|
Set the name of the iconified SDL window, if not specified it is set |
to the same value of I<window_title>. |
|
|
=item B<window_size> |
|
Set the SDL window size, can be a string of the form |
I<width>xI<height> or a video size abbreviation. |
If not specified it defaults to the size of the input video, |
downscaled according to the aspect ratio. |
|
|
=item B<window_fullscreen> |
|
Set fullscreen mode when non-zero value is provided. |
Default value is zero. |
|
=back |
|
|
|
=head3 Interactive commands |
|
|
The window created by the device can be controlled through the |
following interactive commands. |
|
|
=over 4 |
|
|
=item B<q, ESC> |
|
Quit the device immediately. |
|
=back |
|
|
|
=head3 Examples |
|
|
The following command shows the B<ffmpeg> output is an |
SDL window, forcing its size to the qcif format: |
|
ffmpeg -i INPUT -vcodec rawvideo -pix_fmt yuv420p -window_size qcif -f sdl "SDL output" |
|
|
|
=head2 sndio |
|
|
sndio audio output device. |
|
|
=head2 xv |
|
|
XV (XVideo) output device. |
|
This output device allows one to show a video stream in a X Window System |
window. |
|
|
=head3 Options |
|
|
|
=over 4 |
|
|
=item B<display_name> |
|
Specify the hardware display name, which determines the display and |
communications domain to be used. |
|
The display name or DISPLAY environment variable can be a string in |
the format I<hostname>[:I<number>[.I<screen_number>]]. |
|
I<hostname> specifies the name of the host machine on which the |
display is physically attached. I<number> specifies the number of |
the display server on that host machine. I<screen_number> specifies |
the screen to be used on that server. |
|
If unspecified, it defaults to the value of the DISPLAY environment |
variable. |
|
For example, C<dual-headed:0.1> would specify screen 1 of display |
0 on the machine named ``dual-headed''. |
|
Check the X11 specification for more detailed information about the |
display name format. |
|
|
=item B<window_id> |
|
When set to non-zero value then device doesn't create new window, |
but uses existing one with provided I<window_id>. By default |
this options is set to zero and device creates its own window. |
|
|
=item B<window_size> |
|
Set the created window size, can be a string of the form |
I<width>xI<height> or a video size abbreviation. If not |
specified it defaults to the size of the input video. |
Ignored when I<window_id> is set. |
|
|
=item B<window_x> |
|
|
=item B<window_y> |
|
Set the X and Y window offsets for the created window. They are both |
set to 0 by default. The values may be ignored by the window manager. |
Ignored when I<window_id> is set. |
|
|
=item B<window_title> |
|
Set the window title, if not specified default to the filename |
specified for the output device. Ignored when I<window_id> is set. |
|
=back |
|
|
For more information about XVideo see E<lt>B<http://www.x.org/>E<gt>. |
|
|
=head3 Examples |
|
|
|
=over 4 |
|
|
=item * |
|
Decode, display and encode video input with B<ffmpeg> at the |
same time: |
|
ffmpeg -i INPUT OUTPUT -f xv display |
|
|
|
=item * |
|
Decode and display the input video to multiple X11 windows: |
|
ffmpeg -i INPUT -f xv normal -vf negate -f xv negated |
|
|
=back |
|
|
|
|
=head1 SEE ALSO |
|
|
|
ffmpeg(1), ffplay(1), ffprobe(1), ffserver(1), libavdevice(3) |
|
|
=head1 AUTHORS |
|
|
The FFmpeg developers. |
|
For details about the authorship, see the Git history of the project |
(git://source.ffmpeg.org/ffmpeg), e.g. by typing the command |
B<git log> in the FFmpeg source directory, or browsing the |
online repository at E<lt>B<http://source.ffmpeg.org>E<gt>. |
|
Maintainers for the specific components are listed in the file |
F<MAINTAINERS> in the source code tree. |
|
|
|